Thermionic device



July 14-, $931.

A. MCL, McoLsbN 7 11,814,327

THERMIONIC DEVICE Filed March 11, 1927 2 Sheets-Sheet 2 INVENTOR DER MCLEAN mbaLsuM Patented July 14, 1931 UNITED STATES PATENT OFFICE ALEXANDER MCLEAN NICOLSON, OF NEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGN- MENTS, TO FEDERAL TELEGRAPH COMPANY, A. CORPORATION OF CALIFORNIA THERMION'IG DEVICE Application filed March 11, 1927. Serial No. 174,487.

This invention relates to electron discharge devices or electron tubes and more particularly to electron tubes, each of which includes a lurality of thermionic amplifying stages included within the same evacuated envelope.

An important object of this invention is to provide an improved electron tube of the kind containing a plurality of thermionic systems, electrically shielded from each other.

Another object of the invention is to revide efi'ective means for shielding the t ermionic systems in such an electron tube from each other.

provide shields between different thermionic systems in an electron tube, which shields may be utilized as structural elements of the tube, for supporting and reinforcing the various electrodes.

Other objects of the invention are to provide an electron tube having a plurality of thermionic elements arranged around an axis and separated by metallic plate members radiating from said axis, and to provide an electron tube having a plurality of thermio nic systems and a metallic shield device having a compartment for each of said thermionic systems. Other objects and advantageswill appear from the specification.

Another object-of my invention is to provide such a device in which a cathode is used which is common to all the thermionic amli 'n sta es.

p 'l lib f eatues of novelty which I believe to be characteristic of my invention are set forth with particularity in the appended claim. 'My invention itself, however, will best be understood both as to its fundamental principles and as to its practical embodiments, by reference to the specification and Figure 3 is a front elevation, partly broken away, of the structure shown in Figure,

Figure 4 is a plan view illustrating another embodiment of the invention;

Figure 5 is a front elevation, partly broken away, of the structure illustrated in Fig ure Figure 6 is a front elevation illustrating another embodiment of the invention; and

Figure 7 is a view in side elevation of the embodiment illustrated in Figure 6.

In the form of the invention shown in Fig. 1, there is a sealed tube or vessel 1, formed of glass or the like and including a plurality of thermionic systems or elements 2, 3, 4, and 5 arranged in sector-like compartments of a shielding device f suitable A further object of the invention is tomaterial such as metal and comprising a plate-like portion 7 passing through the axis of the tube and between thermionic systems 2 and3 on one side and thermionic systems 4 and 5 on the other side and plate-like elements or partitions 8 and 9 supported on or secured to shield portion 7, portion 8 extending between thermionic elements 3 and 4 and portion 9 extending between thermionic elements 2 and 5.

As herein disclosed, plate or portion 7 of the shield device 6 may be attached at its lower edge to arms 10 secured in the press in stem 11; and said thermionic elements may be supported by arms 13 and 13a, extending outwardly from plate 7, but insulated from each other by suitable means such as glass beads 20.

Each of said thermionic elements may for example comprise a plate element 14 in the form of a cylinder, a grid element 15 in the form of a helix inside the cylinder 14 and a filament 16 inside the helix 15. The filament as here shown, passes through all of the thermionic elements in series and the ends are connected with leads '17 and 18 passing through the press, but it will be understood that this showing is for illustrative purposes and that modifications within the scope of the claim may be made. The grid elements 15 may be connected each with separate leads 19, assing through the press and the plate mem ers 14 may be connected each with separate leads 21 passing through the press. l

The envelope 1 may be mounted in a suitable base of conventional form, hereinafter designated as 12, carrying contacts to which the various leads may be taken.

As illustrated in Figures 2 and 3 in order to simplify the problems of exhausting the tube, each electron tube may be provided with thermionic systems or elements 22, 23 and 24 and corresponding surrounding shields 25, 26 and 27 respectively which may be in the form of closed cylinders in contact with each other. Each of these thermionic elements may, for example, comprise a plate element 28 in the form of a cylinder, :1 grid element 29 in the form of a helix, and a filament 30 and these thermionic elements together with their shields may be arranged in general parallelism with the axis of the tube. According to this embodiment of the invention, the filament 30 of the thermionic elements 22 and 23 may be joined by a connection 31 passing through an opening 32 in the walls of the shields and 26 and insulated therefrom by a suitable insulating device 33, and the filament of the thermionic element 24 may be joined with the filament of the thermionic element 23 by means of a connection 34 passing through the shields 26 and 27 and insulated therefrom by a suitable insulating device 24a. The filaments may be connected either in series or in parallel. The grid elements 29 may be connected each with separate leads 35 passing through the press; the plate elements 28 may be connected each with separate leads 36 passing through the press; and the filament 30 may be connected with leads (not shown) passing through the press. It should be understood that the supporting means (not shown) for the shields may be grounded to the cathode.

In the form illustrated in Figures 4 and 5, the thermionic elements 22, 23 and 24 and their shields 25, 26 and 27 may be arranged in the same general manner as illustrated in Figures 2 and 3, but with the shields out of contact and connected by suitable connecting means 36a. Furthermore, in this form filaments 30 of the thermionic elements 22, 23 and 24 are connected in series, the filament of the element 22 being connected at its lower end with a lead 37a in the press and at its upper end with the filament of the element 23 by a connection 38 above the upper ends of the shields 25 and 26, and the lament of the element 23 being connected at its lower end with the filament of the element 24 by a connection 39 extending beneath the lower ends of the shields 26 and 27, and at its opposite end with lead 375 passing through the press.

In the embodiment of the invention illustrated in Figures 6 and 7, the elements 22, 23 and 24 may be arranged with their axes parallel but turned through a right angle from their position in Figures 2 to 7 inclusive, so that the axis of the shield 27 is perpendicular to the axis of the tube. In this form the shields are shown in contact with each other and the two shields 25 and 26 are connected with the outer ends of supports 40 projecting from the press. The filament 30 of the element 22 may be connected at one end with a lead 41 in the press and at the other end with the filaments of the elements 23 and 24 by connections 42 and 43, the filament of the element 24 being grounded by a connection 45 to its shield 27 which may be connected by suitable means, supports 40 for example, with a lead in the press. The grids 29 may be connected with leads 46 passing through the press and the plates 28 may be connected with suitable leads 47 passing through the press.

While I have shown only a few embodiments of my invention, for the purpose of describing the same and illustrating its principles of operation, it is a parent that vari ous changes and modifications may be made therein without departing from the spirit and scope of my invention. I desire, therefore, that only such limitations shall be imposed as are indicated by the prior art, or are specifically set forth in the appended claim.

Having thus described my invention, I claim: I

An electron tube comprising a plurality of independent sets of electrodes, each set comprising grid, filament and plate electrodes, and each supported within the same evacuated envelope and having their axes parallel; a metallic shield comprising a plurality of intersecting plates portions of which extend between adjacent sets of electrodes, said plates intersecting each other along an axis parallel to the axes of said sets of electrodes, and the axes of said sets of electrodes each being located at substantially the same distance from the axis of intersection of said plates.

In testimony whereof I hereunto aflix my signature. ALEXANDER MCLEAN NICOLSON. 

